Abstract:
The deforestation of tropical forests has been considered as the major driver of the forest cover
change and loss of about 50,000 plant and animal species is attributed to it. Two main
interventions to be adopted to tackle the issue, are (i) the protection of the current forests, (ii)
rehabilitate and restore of degraded forests. This study was carried out in Gishwati Landscapes
located in North–West of Rwanda which include the former Gishwati Forest Reserve. The main
objective of this study was to quantify forest cover change from 2003 to 2015 and compare
current tree species diversity and their distribution in different forest structures (restored and
remnant forests. Supervised classification was done in Erdas Imagine and Arc Map software in
analysing L7-ETM+(2003) and L8 OLI/TIRS (2015) images to quantify land uses and forest
cover changes. From land cover change detection results, two different types of forested areas
were found: (i) undestroyed natural forest areas and (ii) regenerated forest from converted
cropland and pasture in which 120 samplings plots were established and tree species were
recorded. Further analysis was done using PAST for tree species diversity. Supervised
classification gave three main land uses which are cropland, forest, and pasture. Change
detection showed that cropland reduced in size by 25%, forest increased by 5.2 % and pasture by
20%. For tree diversity and species richness, the forest derived from cropland has high species
richness (21), followed equally by forest to forest and pasture to forest (20). Species dominance
index of the remnant forest is higher (0.1998), followed by pasture converted (0.1891) while the
cropland converted to forest come at the last position (0.145). Simpson’s index of forest derived
from cropland was higher (0.855), followed by pasture derived (0.8109) and finally by the
remnant forest (0.8002) while the Species evenness is higher in the forest from cropland (0.4457)
followed by forest converted from pasture (0.3995) and then remnant forest (0.3585). There has
been a positive forest cover from 2003 to 2015 which is beneficial for the sustainability of
biodiversity. Good news is that it has been observed that conversion from cropland to forest can
increase up forest cover than converting pasture to forest. Remnant forest is more abundant in
trees than restored forest which still emphasize role of forest protection before rehabilitation and
restoration.
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Key words
Key words: Gishwati, land use, forest cover change, species richness, tree diversity.
